Hey.. It depends on the number of days you are planning for your visit The must vists are
1.Munnar - 2days minimum
2.Wayanad - 2 days to visit around
3.Kumarukom(highly underrated) - can stay one day too
4.Varkala and Kovalam Kovalam has the treat for sea food lovers and has the best resorts There is still lot to explore if you hav e time can go for Vagamon and Idukki